package demo03usb;

public class Test {
    public static void main(String[] args) {
        PC pc =new PC();
        pc.powerOn();
        //1
        USB device1 =new Mouse();
        pc.useDevice(device1);
        //2
        Keyboard device2 = new Keyboard();
        pc.useDevice(device2);
        //3
        pc.useDevice(new Audio());

        pc.powerDown();
    }
}
